Study the nature of the humoral immune response to syngenic mouse mammary carcinomas. Primary tumors or carcinomas in early transplant in a strain and C3H mice will be studied. Major emphasis of the studies will be the evaluation of the humoral assay for the early detection of antibodies in response to mammary tumor associated antigens. In addition, the specificity of the detected antibodies will be defined. In the first year work will be restricted to the mouse mammary tumor system. In years 2 or 3, if suitable rat carcinoma models are available, the work will be extended to this area.